The purpose of this study is to observe the natural course of food allergy, including both the development of peanut allergy in infants at high risk for developing this allergy, and the resolution of both egg and cow's milk allergy.

Resolution of milk allergy after the age of three years [ Time Frame: Year 10 ] [ Designated as safety issue: No ]

determined by well established criteria with > 95% diagnostic accuracy. Additional (interval analysis) endpoints of egg and milk allergy will be explored in younger children because these allergies may resolve earlier. Common clinical allergy evaluations (e.g., prick skin tests and food-specific IgE antibodies to the 3 targeted foods and common environmental allergens) will be performed and incorporated in the diagnoses of food allergy and atopy.

Resolution of egg allergy after the age of three years [ Time Frame: Year 10 ] [ Designated as safety issue: No ]

determined by well established criteria with > 95% diagnostic accuracy.

Resolution of peanut allergy after the age of three years [ Time Frame: Year 10 ] [ Designated as safety issue: No ]

determined by well established criteria with > 95% diagnostic accuracy.

Resolution of a positive test to peanut after the age of three years (suspected allergy category) [ Time Frame: Year 10 ] [ Designated as safety issue: No ]

determined by well established criteria with > 95% diagnostic accuracy.

Development/persistence of milk allergy after the age of three years [ Time Frame: Year 10 ] [ Designated as safety issue: Yes ]

determined by well established criteria with > 95% diagnostic accuracy.

340 longitudinally followed children with egg and/or milk allergy without elevated peanut specific Immunoglobulin E (IgE), less than 5 kUA/L

Full sibling controls for genetic studies

Approximately 250 not age matched full siblings (i.e., non-step siblings, non-half siblings) will be recruited as an additional control group for genetic studies.

Full sibling controls for mechanistic studies

Approximately 50 not age matched full siblings (i.e., non-step siblings, non-half siblings) will be recruited as an additional control group for mechanistic studies. A subset of this cohort will be without food allergy,

Detailed Description:

This observational study will investigate the developmental immunology of peanut, egg, and milk allergy in a cohort of milk- or egg-allergic children who are at risk for peanut allergy. This strategy will help to delineate, compare, and contrast biological markers and immunologic changes associated with the development of peanut allergy and loss of egg and milk allergy, while simultaneously evaluating important clinical and environmental influences likely to account for the recent rise in the prevalence of these allergies. The hallmark of food-allergic disease is the production of food-specific Immunoglobulin E (IgE) antibodies that represent an end result of a T helper 2 (Th2) influenced immune response. Currently, there is only a limited understanding of the mechanisms involved in the developmental course of food allergies. To effectively prevent or reverse the progression of food allergy, immune interventions will be needed. Furthermore, it is likely that successful strategies will need to be directed to those persons at identifiable risk (e.g., who have biomarkers associated with development of peanut allergy).

Eligibility

Ages Eligible for Study:

3 Months to 15 Months (Child)

Genders Eligible for Study:

Both

Accepts Healthy Volunteers:

No

Sampling Method:

Non-Probability Sample

Study Population

Children with milk or egg allergy who are at risk for peanut allergy

Criteria

Inclusion Criteria for Children with Food Allergy: Participants who meet all of the following criteria are eligible for enrollment as study participants:

Atopic dermatitis evaluation

Either

A convincing clinical history of cow's milk (and/or egg) allergy and a positive prick skin test (≥ 3mm larger than the negative control) to cow's milk (and/or egg, if egg allergy history), or

Moderate to severe atopic dermatitis at the time of enrollment (or by a history prior to removal of milk and/or egg from the maternal (if breastfed) or infant diet) and a positive prick skin test to milk or egg, or

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Please refer to this study by its ClinicalTrials.gov identifier: NCT00356174